Bob,
The terms Mailboat, Boat Train, Banana Boat etc were coined by people who had nothing to do with the sea, and the general public just went along with it. I knew the difference between a ship and a boat before I was ten years old, simply by reading about them! My parents always called them boats! I was once made to stand in a corner at infants school for declaring that a derrick was a crane on a ship and that a barque (bark) was not so-called because it was made of wood!
Sailing ships were not long and slender, although looking at the plan of Forteviot, you may think so. They were very wide, and very deep. Look how much is under water (the red part). When it came to breaking their backsin storms, not many of them did. In fact, I can only think of one, the 6-masted schooner Wyoming (See image above). That one broke up whilst lying at anchor in bad weather, but there was a reason. She was an enormous ship, well over 300-feet long, and to make matters worse, she was built of softwood! Far too big for a softwood ship. British shipbuilding changed over to iron and steel in the early 1870s for ocean going ships. They were immensely strong, often with plating over an inch thick for ships of only two thousand tons or so. I have sailed in a 32,000 ton tanker with hull plating only 5/8 inch thick!
Bob